# CVE-2021-20202: Temporary Directory Hijacking Vulnerability in Keycloak

> Attackers can access or modify Keycloak temporary files by pre-creating directories with wider permissions, compromising data confidentiality and integrity.

- **Severity:** High 7.3 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 12 May 2021
- **Updated:** 3 Aug 2024
- **Also known as:** GHSA-6xp6-fmc8-pmmr

## What is CVE-2021-20202?

CVE-2021-20202 is a high-severity vulnerability in Redhat Keycloak, published on 12 May 2021. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

A flaw was found in keycloak. Directories can be created prior to the Java process creating them in the temporary directory, but with wider user permissions, allowing the attacker to have access to the contents that keycloak stores in this directory. The highest threat from this vulnerability is to data confidentiality and integrity.

Weakness: CWE-377 (DEPRECATED: Insecure Temporary File)

## Which versions are affected by CVE-2021-20202?

2 open source packages ship an affected version, including org.keycloak:keycloak-core. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `org.keycloak:keycloak-core` | Maven | All versions | 13.0.0 |
| `org.keycloak:keycloak-core` | Maven | All versions | 13.0.0 |

Products: Redhat Keycloak.

## How do I fix CVE-2021-20202?

Upgrade org.keycloak:keycloak-core to 13.0.0 or later.

## Is CVE-2021-20202 being exploited?

There is no known exploitation of CVE-2021-20202 in the wild and no public exploit code.

## Other vulnerabilities in Redhat Keycloak

- [CVE-2022-4361](https://insights.sbomify.com/CVE-2022-4361/): Keycloak vulnerable to cross-site scripting when validating URI-schemes on SAML and OIDC (critical 10.0)
- [CVE-2022-1245](https://insights.sbomify.com/CVE-2022-1245/): Keycloak vulnerable to privilege escalation on Token Exchange feature (critical 9.8)
- [CVE-2021-20195](https://insights.sbomify.com/CVE-2021-20195/): keycloak Self Stored Cross-site Scripting vulnerability (critical 9.6)
- [CVE-2019-14910](https://insights.sbomify.com/CVE-2019-14910/): Keycloak Authentication Error (critical 9.3)
- [CVE-2019-14909](https://insights.sbomify.com/CVE-2019-14909/): Keycloak Authentication Error (critical 9.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-20202 and fix it if it is affected.

What it is: CVE-2021-20202 is a high-severity vulnerability in Redhat Keycloak, published on 12 May 2021. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2021-20202 in the wild and no public exploit code.

Affected packages and fixed versions:
- org.keycloak:keycloak-core (Maven): affected all versions; fixed in 13.0.0
- org.keycloak:keycloak-core (Maven): affected all versions; fixed in 13.0.0

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2021-20202/ (Markdown: https://insights.sbomify.com/CVE-2021-20202/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-20202
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-20202
- OSV: https://osv.dev/vulnerability/CVE-2021-20202

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-20202/
Summaries are generated and may contain mistakes; the official description above is the record.